1. Technical Field
The present invention relates to a liquid ejecting apparatus such as an ink jet printer and a method of controlling the liquid ejecting apparatus, and more particularly, to a liquid ejecting apparatus capable of controlling ejection of a liquid by applying an ejection driving pulse to a pressure generation unit and a method of controlling the liquid ejecting apparatus.
2. Related Art
A liquid ejecting apparatus is an apparatus which includes a liquid ejecting head having nozzles ejecting a liquid and ejects various kinds of liquids from the liquid ejecting head. A representative example of the liquid ejecting apparatus is an image printing apparatus such as an ink jet printer (hereinafter, simply referred to as a printer) which includes an ink jet print head (hereinafter, simply referred to as a print head) as a liquid ejecting head and prints an image or the like by ejecting and landing liquid-like ink from nozzles of the print head on a print medium (landing target) to form dots. In recent years, the liquid ejecting apparatus has been applied not only to the image printing apparatus, but also various manufacturing apparatuses such as an apparatus manufacturing a color filter such as a liquid crystal display.
For example, a printer includes a nozzle row (nozzle group) in which a plurality of nozzles are arranged. In the printer, an ejection driving pulse is applied to a pressure generation unit (for example, a piezoelectric vibrator or a heating device) to drive the pressure generation unit, and a pressure variation is applied to a liquid in a pressure chamber to eject the liquid from the nozzles communicating the pressure chamber. In a printer using a piezoelectric vibrator as a pressure generation unit, in general, ink is ejected from nozzles by first expanding a pressure chamber preliminarily (expansion step), holding the expansion state for a given time (hold step), and then rapidly contracting the pressure chamber (contraction step) to pressurize the ink in the pressure chamber (for example, see JP-A-2006-142588).
However, a printer is configured to eject different kinds of ink, for example, black ink formed of self-dispersion type pigment and color ink formed of resin dispersion type pigment. The self-dispersion pigment is a pigment which can be dispersed or dissolved in a solvent without using a surface acting agent or a dispersion agent such as resin. An example of the self-dispersion pigment includes carbon black ink. The resin dispersion type pigment is a pigment which is dispersed in a solvent using a water-soluble resin, such as an acryl-based resin, methacryl-based resin, vinyl acetate resin, or styrene-acryl-based resin, as a dispersion agent. The resin dispersion type pigment is mainly used for color ink. The ink formed of the resin-dispersion type pigment has the feature that when the ink is ejected under the same conditions, the rear end portion of the ejected ink tends to become a tailed portion like a tail, compared to the ink formed of the self-dispersion type pigment.
That is, when the color ink of which the rear end portion easily becomes a tailed portion is ejected in the configuration in which the black ink and the color ink are ejected using a driving signal (ejection pulse), the rear end tail portion of a preceding main liquid droplet is separated from the main liquid droplet and becomes a satellite liquid droplet in some cases. In the configuration in which the print head is moved relative to the print medium to perform printing, the landing positions of the main liquid droplet and satellite droplet on a print medium are distant from each other. A difference between the landing positions of the main liquid droplet and the satellite liquid droplet may deteriorate the quality of a printed image.